Particle-Based Delivery of HIV Env Immunogens: A major focus of HIV vaccine research has been the development of immunogens that elicit broadly neutralizing antibody responses targeting the envelope protein (Env). While the field has predominantly focused on immunogen design and soluble antigens, the targeted and controlled delivery of antigens has not received much attention and is a gap in the HIV field that needs to be addressed. Tailored immunogens (such as Envs, monomers, native and/or native-like trimers, nucleic acids/RNA) combined with effective multivalent antigenic display on nanoparticles for delivery may provide a strategy to promote strong and long-lived neutralizing antibody responses against HIV and direct affinity maturation toward HIV neutralizing antibodies.